#include "codegen.h"

#include <mie/ir/block.h>
#include <mie/ir/func.h>
#include <mie/ir/module.h>

struct block_codegen_state {
	struct code_generator_state s_base;
	struct code_generator_scope *s_scope;
	struct codegen_var_map s_vars;

	/* the value of the final expression in the block */
	struct mie_value *s_result;
};

static struct code_generator_result gen_expr(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;
	struct mie_builder *builder = gen->c_builder;
	struct mie_func *current = mie_builder_get_current_func(builder);

	codegen_push_generator(
		gen, CODE_GENERATOR_EXPR, CODEGEN_F_IGNORE_RESULT, NULL);
	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
}

static struct code_generator_result gen_for_loop(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	codegen_push_generator(
		gen, CODE_GENERATOR_FOR_LOOP, CODEGEN_F_IGNORE_RESULT, NULL);
	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
}

static struct code_generator_result gen_while_loop(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	codegen_push_generator(
		gen, CODE_GENERATOR_WHILE_LOOP, CODEGEN_F_IGNORE_RESULT, NULL);
	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
}

static struct code_generator_result gen_return(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;
	struct mie_builder *builder = gen->c_builder;
	struct mie_func *current = mie_builder_get_current_func(builder);

	enum ivy_status status = IVY_OK;

	if (status != IVY_OK) {
		return CODEGEN_RESULT_ERR(status);
	}

	codegen_push_generator(gen, CODE_GENERATOR_RETURN, 0, NULL);
	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
}

static struct code_generator_result gen_loop_break(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;

	if (!state->s_loop_break_target) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	mie_builder_br(gen->c_builder, state->s_loop_break_target);

	block->s_result = mie_ctx_get_null(gen->c_ctx);
	return CODEGEN_RESULT_OK(0);
}

static struct code_generator_result gen_loop_repeat(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;

	if (!state->s_loop_repeat_target) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	mie_builder_br(gen->c_builder, state->s_loop_repeat_target);

	block->s_result = mie_ctx_get_null(gen->c_ctx);
	return CODEGEN_RESULT_OK(0);
}

static enum ivy_status state_init(
	struct ivy_codegen *gen, struct code_generator_state *state,
	uintptr_t argv, void *argp)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;
	codegen_var_map_init(&block->s_vars);

	return IVY_OK;
}

static enum ivy_status state_fini(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct code_generator_value *result)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;
	code_generator_value_set_mie_value(result, block->s_result);
	codegen_var_map_fini(&block->s_vars);
	return IVY_OK;
}

static struct code_generator_result value_received(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct code_generator_value *value)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;
	block->s_result = code_generator_value_get_mie_value(value);
	return CODEGEN_RESULT_OK(0);
}

static enum ivy_status define_var(
	struct ivy_codegen *gen, struct code_generator_state *state,
	const char *ident, const struct codegen_var *var)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;
	return codegen_var_map_put(&block->s_vars, ident, var);
}

static enum ivy_status resolve_var(
	struct ivy_codegen *gen, struct code_generator_state *state,
	const char *ident, struct codegen_var *var)
{
	struct block_codegen_state *block = (struct block_codegen_state *)state;
	struct codegen_var *result = NULL;
	enum ivy_status status
		= codegen_var_map_get(&block->s_vars, ident, &result);

	if (status != IVY_OK) {
		return status;
	}

	memcpy(var, result, sizeof *var);
	return IVY_OK;
}

struct code_generator block_generator = {
	.g_type = CODE_GENERATOR_BLOCK,
	.g_state_size = sizeof(struct block_codegen_state),
	.g_state_init = state_init,
	.g_state_fini = state_fini,
	.g_value_received = value_received,
	.g_node_generators = {
		NODE_CODEGEN(FOR_LOOP, gen_for_loop),
		NODE_CODEGEN(WHILE_LOOP, gen_while_loop),
		NODE_CODEGEN(RETURN, gen_return),
		NODE_CODEGEN(LOOP_BREAK, gen_loop_break),
		NODE_CODEGEN(LOOP_REPEAT, gen_loop_repeat),
	},
	.g_expr_generator = gen_expr,
	.g_define_var = define_var,
	.g_resolve_var = resolve_var,
};